EP1057928A2 - Soft roll and process for making such a roll - Google Patents

Abstract

The elastic roller, especially for polishing a paper web, has a hard roller core (1) especially of metal with a cladding of an elastic matrix material (6). The roller cladding is covered by a metallic layer of metal fibers and/or metal-coated fibers (3). The fibers (3) are gathered into one or more fiber bundles (4) and/or rovings and/or a fiber web and/or the metallic covering is in a single fiber layer. The metallic covering layer has a radial thickness of 2-30 mu m and preferably 5-10 mu m and/or the surface of the metallic covering is ground and especially polished and/or the metallic surface has an Ra value of ≤ 0.05 mu m and especially ≤ 0.03 mu m. The metal for the outer covering layer has a melting point of ≤ 600 degrees C and preferably about 480 degrees C or less. A filling material of fibers (3) is embedded in the matrix material (6) which has a greater stiffness than the matrix material (6) and/or has a thermal conductivity which is greater than the matrix material. The thermal coefficient of expansion of the filling material fibers (3) is less than that of the matrix material (6) and is generally equal to that of the roller core (1) and/or the filling material is of fibers of carbon and/or glass and/or metal. The fibers for the filling material (3) are especially as fiber bundles (4) and/or rovings and/or a fiber web, and at least part of the fibers (3) are of the same material as the fibers in the outer covering layer and/or the fibers (3) in the fiber bundles (4) or rovings or web are used at least partially both for the matrix material (6) and the outer metallic covering layer. At least part of the fibers, and preferably the majority, are aligned in an axial and/or radial direction and/or in a statistical alignment distribution and/or they are in a fiber layer or in radially successive fiber layers. Additional filling materials can be added to the matrix especially as fibers or powder of quartz and/or a polymer. The matrix material (6) is a plastics and especially a heat-setting plastics or a thermoplastic and/or it is a resin/hardener combination. An Independent claim is included for a cladded roller production process where the metallic covering layer is wound around the elastic roller core cladding, using a number of metal fibers and/or metal-coated fibers. The fibers are in one or more fiber bundles and/or rovings and/or a fiber web. One roving is composed of a number of neighboring fibers of the same type and/or a single layer is wound to form the metallic covering layer. Before the fibers are wound around the roller cladding, they are coated with metal and especially through a metal bath. Or the dry fibers are wound around the roller cladding while dry, and during or after winding they are coated with a molten metal. Or, to form the elastic core cladding, the fibers are impregnated with liquid matrix material and wound around the roller core as bundles and/or rovings and/or a web. Before winding, the fibers are coated with the matrix material especially in a matrix bath, or they are dry while being wound and during or after the winding they are treated with the liquid matrix material. After the elastic cladding has been formed around the roller core, the same fiber bundles and/or rovings and/or web are used to form the outer metallic covering layer. The fibers are synthetic and/or of carbon and/or after the feed of metal and/or metal-coated fibers the outer metallic layer is ground and especially polished and/or the filling material is embedded in the matrix especially as fibers or powder of carbon and/or glass.

Description

The present invention relates to a roller, in particular for smoothing of paper webs, with a hard one consisting in particular of metal Roll core with an elastic matrix material on the outside comprehensive elastic reference layer and one on the Outside of the elastic reference layer provided metallic Cover layer is provided. Furthermore, the invention is based on a method directed to making such a roller.

Elastic rolls of this type are used, for example, when satinizing paper webs. An elastic roller forms a press nip together with a hard roller through which the paper web to be processed is passed. While the hard roller has a very smooth surface, for example made of steel or chilled cast iron, and is responsible for smoothing the side of the paper web facing it, the elastic roller acting on the opposite side of the paper web causes the paper web to be leveled and compressed in the press nip. The size of the rollers is 3 to 12 m in length and 450 to 1500 mm in diameter. They withstand line forces up to 600 N / mm and compressive stresses up to 130 N / mm ² .

Since the tendency in papermaking is that the satin in Online operation takes place, i.e. that the the paper machine or coating machine leaving the paper web directly through the paper smoothing device (Calender) is guided to the rollers of the smoothing device higher demands in particular with regard to temperature resistance than previously posed. Due to the high required in online operation Transport speeds of the paper web and the associated high rotational speeds of the calender rolls, their nip frequency, that is the frequency at which the reference compresses and again is relieved, increased, which in turn leads to increased roller temperatures leads. These high temperatures, which arise in online operation, lead to problems with known elastic rollers until destruction of the plastic covering. On the one hand are known Plastic coverings maximum temperature differences of about 20 ° C over the The width of the roller is permissible and on the other hand they are for the coating Usually plastics used are much higher Thermal expansion coefficients than those commonly used Steel rollers or chill cast rollers, so that by an increase in temperature high axial tensions between the steel roller or chilled iron roller and the associated plastic coating occur.

Due to these high voltages associated with particular points occurring heating points within the plastic coating So-called hot spots can occur, at which a detachment or even the plastic layer bursts open.

These hot spots occur especially when in addition to mechanical stresses and the relatively high temperature crystallization points in the form of, for example, faulty bonds, deposits or above-average indentations of the elastic covering, for example due to folds or foreign bodies on the paper web, available. In these cases, the temperature at these crystallization points rise from the usual 80 ° C to 90 ° C to over 150 ° C, whereby the aforementioned destruction of the plastic layer takes place.

A roller, the elastic reference layer with an additional metal coating is known from DE-A-4126232. Through the Metallic cover layer is the thermal conductivity of the outside of the Roll increased so that undesirable occurring within the press nip Heat can be dissipated quickly and the temperature during the Treatment of the web can be kept essentially constant can.

The problem with a metallic reference layer is that the elasticity the surface of the roller depending on the thickness of the metallic reference layer decreases. If the metallic cover layer is chosen too thick, so the elasticity of the surface of the roller is so low that the smoothing. result suffers. Furthermore, the application of a corresponding thin metal layer is relatively expensive and it is difficult to get a metal layer the desired small thickness evenly over the entire Distribute roller surface. In addition, the connection between the elastic reference layer and the metallic cover layer in insufficient in many cases, so that the metal comes off during operation Cover layer can take place.

It is an object of the present invention to provide a roller Specify the type mentioned, a good at least on its surface Has thermal conductivity, the metallic top layer is simple and inexpensive to manufacture and safe with the underlying elastic Reference layer should be connected. Furthermore, a procedure is said to manufacture such a roller.

The part of the task relating to the roller is based on the invention solved by a roller of the type mentioned in that the metallic cover layer made of metal fibers and / or of metal-coated Fibers. A corresponding method according to the invention is characterized in that for the production of the metallic cover layer a variety of metal fibers and / or metal-coated Fibers is wound onto the elastic reference layer.

Through the use of metal fibers or metal-coated fibers a very thin layer can be used to form the metallic cover layer Covering layer are generated, which, moreover, when using metal-coated fibers and suitable fiber material, a higher Elasticity has a covering layer made of pure metal. The metallic cover layer ensures good thermal conductivity Surface of the roller is achieved, so that in operation within the press nip occurring heat can be quickly dissipated to the outside. This ensures that the temperature during treatment the web in the press nip are kept substantially constant can.

Furthermore, in particular by radially inward from the metallic Fibers protruding into the elastic cover layer the connection between the metallic cover layer and the elastic Reference layer can be improved so that a detachment of the cover layer is largely excluded in operation.

According to an advantageous embodiment of the invention, the fibers are in one or more fiber bundles and / or fiber rovings and / or Fiber fleeces summarized. Especially in the formation of the metallic Cover layer through metal-coated or existing metal Fiber rovings, which essentially consist of a large number of single-layered layers Fibers consist of a very thin layer of metal created with great flexibility.

The metallic cover layer can preferably have a radial thickness of between approx. 2 µm and 30 µm, preferably between approx. 5 µm and 10 µm have.

The surface of the metallic cover layer is preferably ground and in particular, polished in order to achieve the smoothest possible roller surface to produce high quality paper create. The surface of the metallic cover layer can be one Have an Ra value of less than 0.05 µm, in particular less than Is 0.03 µm.

According to a preferred embodiment of the invention, the metal is the Cover layer at low temperatures, especially at temperatures below about 600 ° C, preferably at about 480 ° C or below melting Metal, especially zircon. By using a low melting Metal is used to manufacture one designed according to the invention Roller simplified because both the fiber material and the matrix material must have a lower heat resistance than when used of metal melting at high temperatures. The usage Zircon is advantageous because zircon is a particularly good bond with those commonly used to form the elastic reference layer Plastic materials received. This will make the connection between the elastic reference layer and the metallic cover layer further improved.

Fillers, which are preferred, are advantageously embedded in the matrix material have a greater stiffness than the matrix material, so that the required rigidity of the elastic reference layer is achieved. Furthermore, the thermal conductivity of the fillers is advantageously greater than that Thermal conductivity of the matrix material. This ensures that the Heat at overheating points occurring within the elastic reference layer quickly, for example, to the roll core or to the metallic one Top layer and from there is completely removed laterally.

The thermal expansion coefficient of the fillers is advantageously less than the coefficient of thermal expansion of the matrix material and in particular essentially the same as the coefficient of thermal expansion of the Roll core. In this way it can be set that the total coefficient of thermal expansion the elastic reference layer is smaller than the coefficient of thermal expansion of the matrix material, so that the by the longitudinal stresses occurring during operation between the roller core and the elastic reference layer reduced or completely can be compensated. It is advantageous that the fillers consist of carbon and / or glass and / or metal.

According to a preferred embodiment of the invention, the fillers are as fibers, in particular as fiber bundles and / or as fiber rovings and / or nonwoven formed. It is advantageous that at least part of the fibers of the same material as the fibers of the metallic Cover layer are formed and in particular the fibers of the metallic cover layer and those embedded in the matrix material Fibers at least partially fibers of the same fiber bundle, fiber rovings and / or nonwoven. Become both the elastic reference layer as well as the metallic cover layer essentially through the the same fiber bundle, fiber rovings or nonwovens formed, so the elastic cover layer and the metallic cover layer a uniform, continuous reinforcement formed by the fibers. A replacement the metallic cover layer from the elastic reference layer is on practically excluded this way.

According to the invention, a multiplicity is used to produce an elastic roller of metal fibers and / or of metal-coated fibers on the elastic cover layer wound. The fibers can be in shape one or more fiber bundles, fiber rovings or nonwovens on the Reference layer are wound up, in particular for production essentially the thinnest possible elastic metallic cover layer single-layer fiber layer is wound.

The fibers are pre-wound onto the elastic reference layer preferably coated with metal, especially drawn through a metal bath, or wound up substantially dry on the reference layer and during or after winding with the metal, especially in liquid Form, coated or applied.

Similarly, to create the elastic reference layer in particular fibers impregnated with liquid matrix material, in particular in the form of one or more fiber bundles and / or fiber rovings and / or non-woven fabrics are wound on the roll core. Here can the fibers before winding on the roll core with the matrix material be coated, especially drawn through a matrix bath become. However, it is also possible that the fibers are essentially be wound up dry on the roll core and during or after winding with the matrix material, especially in liquid form be coated or applied.

The elastic reference layer and the metallic cover layer are advantageous through the same fiber bundles and / or fiber rovings and / or If nonwoven fabrics are used, a roller designed according to the invention can be special can be easily produced by a single winding process. In In this case, the fibers can first be used to produce the elastic The reference layer is drawn through a matrix bath and wound onto the roll core until the elastic reference layer has the desired thickness has reached. Then the same fibers can continue on the just generated elastic reference layer are wound up, being be passed through a metal bath beforehand. Because in this case the elastic Reference layer and the metallic cover layer from the same fiber bundles exist, is a detachment of the metallic cover layer from the elastic cover layer practically excluded.

After applying the metal fibers and / or metal-coated fibers the surface of the metallic cover layer is applied to the reference layer ground and in particular polished until the desired surface quality the elastic roller is reached. Further advantageous embodiments of the invention are in the subclaims specified.

Fig. 1

einen schematischen Darstellung einer erfindungsgemäß ausgebildete elastische Walze bei der Erzeugung der elastischen Bezugsschicht,

Fig. 2

einen schematischen Querschnitt durch die Walze gemäß Figur 1 mit vollständiger elastischer und metallischer Beschichtung und

Fig. 3

eine Detailansicht aus Fig. 2.

The invention is described below using an exemplary embodiment with reference to the drawings; in this show:

Fig. 1

2 shows a schematic illustration of an elastic roller designed according to the invention when producing the elastic reference layer,

Fig. 2

a schematic cross section through the roller according to Figure 1 with complete elastic and metallic coating and

Fig. 3

2 shows a detailed view from FIG. 2.

The roller shown in Fig. 1 comprises, for example, made of steel or Chilled cast iron existing core 1, which is rotatable about an axis 2 is. A large number of fibers 3, which are combined to form a fiber bundle 4 1, on the outside of the roll core 1 wound up. The fiber bundle 4 is before winding on the roll core 1 by a schematically represented impregnation device 5 out where it is coated with liquid matrix material 6.

So many layers of fiber bundles 4 are wound on the roll core 1, until an elastic reference layer 7 (see Figs. 2 and 3) of the desired Thickness arises. Either a fiber bundle 4 multiple or several separate fiber bundles 4 single or multiple the roll core 1 are wound.

Then the fiber bundle 4 is further developed on the fully formed elastic reference layer 7 wound, instead of the liquid Matrix material via the impregnation device 5 or another impregnation device the fibers 3 of the fiber bundle 4 before winding be coated with liquid metal. This way the elastic Reference layer 7 a metallic cover layer 8 (see Fig. 2 and 3) generated, which advantageously from a single or at least from a small Number of fiber layers with metal coating. Are the Fibers 3 already formed as metal fibers, so you can create them the cover layer 8 are heated so far that they are at least in the surface area melt. In this way, the metal fibers melt together and after winding it becomes a homogeneous metallic Cover layer 8 generated. Basically, it is also possible that the metal fibers only after winding up to the extent that their surface melts, creating a homogeneous top layer.

2 and in particular the detailed view according to FIG. 3 shows that the metallic cover layer 8 consists essentially of one of the fiber bundle 4 formed fiber layer is formed, which is coated with metal 9 or is embedded in it. The elastic reference layer is corresponding 7 from a plurality of spirally arranged, through which Fiber bundle 4 formed fiber layers built in the matrix material 6 are embedded.

The size and thickness ratios in FIGS. 2 and 3 are not to scale executed because at an actual thickness of the metallic Cover layer of 10 µm, for example, this is not visible in the figures would.

3 clearly shows that the metallic Cover layer 8 and the elastic reference layer 7 as a carrier for the matrix material 6 or the metal 9 have the same fiber bundle 4 that out and out of the elastic reference layer 7 at the point denoted by 10 enters the metallic cover layer 8. The elastic reference layer 7 and the metallic cover layer 8 thus have through the fiber bundle 4 a uniform structure so that they are safe over the fiber bundle 4 are interconnected.

After the metallic cover layer 8 has been completely formed, the surface thereof 11 ground and possibly polished, so that the surface 11 of the invention Roller is extremely smooth.

The single-layer fiber layer formed by the fiber bundle 4 in the metallic Cover layer 8 gives it a very stable structure and causes at the same time high when using suitable fiber materials Flexibility of the metallic cover layer 8, so that the coating of the Roll designed according to the invention despite the metallic cover layer 8 has great flexibility.

Reference list

1

Roll core

2nd

axis

3rd

Fibers

4th

Fiber bundle

5

Impregnation device

6

Matrix material

7

elastic cover layer

8th

metallic top layer

9

metal

10th

Transition point

11

surface

Claims (15)

Roller, in particular for smoothing paper webs, with a hard roller core (1) consisting in particular of metal, which is provided on the outside with an elastic reference layer (7) comprising an elastic matrix material (6) and one on the outside of the elastic reference layer (7) metallic cover layer (8) is provided,
characterized,
that the metallic cover layer (8) consists of metal fibers and / or of metal-coated fibers (3). Roll according to claim 1,
characterized,
that the fibers (3) are combined in one or more fiber bundles (4) and / or fiber rovings and / or fiber fleeces and / or that the metallic cover layer (8) consists of an essentially single-layer fiber layer. Roller according to claim 1 or 2,
characterized,
that the metallic cover layer (8) has a radial thickness of between approximately 2 µm and 30 µm, preferably between approximately 5 µm and 10 µm and / or that the surface of the metallic cover layer (8) is ground and in particular polished and / or that the surface (11) of the metallic cover layer (8) has an Ra value which is less than 0.05 µm, in particular less than 0.03 µm. Roller according to one of the preceding claims,
characterized,
that the metal (9) of the cover layer (8) is a metal, in particular zircon, which melts at low temperatures, in particular at temperatures below approximately 600 ° C., preferably at approximately 480 ° C. or below. Roller according to one of the preceding claims,
characterized,
that fillers (3) are embedded in the matrix material (6), in particular that the fillers (3) have a greater rigidity than the matrix material (6) and / or that the thermal conductivity of the fillers (3) is greater than the thermal conductivity of the matrix material ( 6). Roll according to claim 5,
characterized,
that the thermal expansion coefficient of the fillers (3) is smaller than the thermal expansion coefficient of the matrix material (6) and in particular is essentially the same size as the thermal expansion coefficient of the roller core (1) and / or that the fillers (3) made of carbon and / or glass and / or consist of metal. Roller according to one of claims 5 or 6,
characterized,
that the fillers are formed as fibers (3), in particular as fiber bundles (4) and / or as fiber rovings and / or as fiber fleece, and in particular that at least some of the fibers (3) are made of the same material as the fibers of the metallic cover layer ( 8) and / or that the fibers (3) of the metallic cover layer (8) and the fibers (3) embedded in the matrix material (6) are at least partially fibers of the same fiber bundle (4), fiber rovings and / or fiber fleece. Roller according to address 7,
characterized,
that at least a part, in particular a predominant part of the fibers (3) are aligned in the axial direction and / or that at least a part, in particular a predominant part of the fibers (3) are aligned in the radial direction and / or that at least a part, in particular a predominant part of the fibers (3) are aligned in a statistically distributed manner and / or that the fibers (3) are arranged in a fiber layer or in radially successive fiber layers. Roll according to one of claims 5 to 8,
characterized,
that in addition to the fillers (3), further fillers, in particular in the form of fibers or powder, are arranged in the matrix material, in particular that the further fillers consist of quartz and / or PTFE. Roller according to one of the preceding claims,
characterized,
that the matrix material (6) is a plastic, in particular a thermoset or a thermoplastic and / or that the matrix material (6) is a resin / hardener combination. Method for producing an elastic roller with an adherent roller core consisting in particular of metal, which is provided with an elastic reference layer comprising an elastic matrix material and a metallic cover layer provided on the outside of the elastic reference layer, in particular for producing a roller according to one of the preceding claims,
characterized,
that a plurality of metal fibers and / or of metal-coated fibers is wound onto the elastic reference layer to produce the metallic cover layer. A method according to claim 11,
characterized,
that the fibers are wound onto the reference layer in the form of one or more fiber bundles and / or fiber rovings and / or fiber nonwovens, a roving in each case consisting of a plurality of fibers of the same type lying next to one another, and / or that a substantially to produce the metallic cover layer single-layer fiber layer is wound. The method of claim 11 or 12,
characterized,
that the fibers are coated with metal, in particular through a metal bath, before being wound onto the elastic reference layer, or that the fibers are wound onto the reference layer essentially dry and coated with the metal, in particular in liquid form, during or after the winding or applied, or that in order to produce the elastic reference layer, in particular fibers impregnated with liquid matrix material, in particular in the form of one or more fiber bundles and / or fiber rovings and / or fiber fleeces, are wound on the roller core, the fibers in particular being wound onto the roller core coated with the matrix material, in particular pulled through a matrix bath, or the fibers are wound up essentially dry on the roll core and coated or acted upon during or after the winding up with the matrix material, in particular in liquid form. Method according to one of claims 12 or 13,
characterized,
that after forming the elastic reference layer, the same fiber bundles and / or fiber rovings and / or non-woven fabrics are used to produce the metallic cover layer. Method according to one of claims 11 to 14,
characterized,
that soft synthetic fibers, for example of aramide, and / or carbon fibers are used as fibers and / or that after the metal fibers and / or the metal-coated fibers have been applied to the reference layer, the surface of the metallic cover layer is ground and in particular polished and / or that into the Matrix material fillers, in particular fibers or powders, preferably made of carbon and / or glass, can be embedded.

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